Strut for interconnecting reinforcement rods

ABSTRACT

A strut for interconnecting a pair of spaced-apart reinforcement rods is formed of an elongated bar having an integral hook at each end. A body of synthetic-resin is molded on each of the hooks and is formed within the respective hook with a seat adapted to receive on of the rods. This seat is offset from the center of curvature of the respective hook and is formed with a pair of deflectable tongues at spaced locations along the bar, each tongue extending at an acute angle to the bar at the location. The deflectable tongues have ends snugly engageable against a rod received in the seat.

United States Patent [191 Wiirth July 22, 1975 [54] STRUT FOR INTERCONNECTING 3,530,634 9/1970 Adams 52/687 REINFORCEMENT RODS 3,694,989 10/1972 Oliver et a1. 52/687 Inventor: Reinhold Wiirth, Schliffenstrasse,

711 1 Geisbach Kries Kunzelsau, Germany Filed: Feb. 25, 1974 Appl. No.: 445,237

Foreign Application Priority Data Dec. 6, 1973 Germany 2360789 References Cited UNITED STATES PATENTS 7/1965 Michalak 52/686 10/1967 Berry 52/684 10/1969 Yelsma 52/684 Primary ExaminerErnest R. Purser Assistant Examirzer-James L. Ridgill, Jr. Attorney, Agent, or FirmKarl F. Ross; Herbert Dubno [57] ABSTRACT A strut for interconnecting a pair of spaced-apart reinforcement rods is formed of an elongated bar having an integral hook at each end. A body of syntheticresin is molded on each of the hooks and is formed within the respective hook with a seat adapted to receive on of the rods. This seat is offset from the center of curvature of the respective hook and is formed with a pair of deflectable tongues at spaced locations along the bar, each tongue extending at an acute angle to the bar at the location. The deflectable tongues have ends snugly engageable against a rod received in the seat.

7 Claims, 2 Drawing Figures e s ly-Ma new. 2'. ling |i v I 1 Y STRUT FOR IN'TERCONNECTING REINFORCEMENT RODS FIELD Tl-IE INV ENTION The present invention relates to a strut for interconnecting reinforcement rods of reinforcedconcrete structures. Morepartieularly this invention concerns such a strut which is hooked between the reinforce ment rods in a concrete wall or the like, the rods running parallel to the faces of the wall and the strut extending perpendicularly thereto.

BACKGROUND OF THE INVENTION In the construction of a concrete wall or the like it is common practice to form a pair of planar arrays of long reinforcement rods. Each of these arrays is formed of two sets of rods. the rods in each set being parallel to each other and extending at right angles to the rods of the other set. Thus a pair of spaced-apart planar grids are formed which are imbedded in the finished wall.

It is known to interconnect these two grids by means of short reinforcement-rod struts formed at each end with a hook. Each strut has an overall length equal to slightly less than the desired thickness of the wall, and each is adapted to be hooked over a rod of each of the grids to hold the grids the desired distance apart. Each hook is in addition formed with a synthetic-resin holder body which extends longitudinally outwardly from the strut and which is adapted to engage the inside of the forms used in the making of the concrete wall. In addition each body is formed internally with a flexible stop so that the reinforcement rod engaged therein does not slip out. Thus the main reinforcing rods, that is those rods lying parallel to the surface of the wall, are set in place and prefabricated struts of the desired overall length, that is a length corresponding to the desired wall thickness, are clipped in place on the two arrays of main reinforcement rods so as to hold these main reinforcement rods at an exact spacing between the two forms. In this manner it is possible for even a relatively unskilled workman to set up the reinforcing structure for a concrete wall. a job which is normally onerous in the extreme. and which usually requires relatively careful workers Nonetheless it has been found in such arrangements that the spacing strut comes disattached. This is often due to the fact that the main reinforcement rods are frequently subjected to considerably shock. so that the books at the ends of the struts become disengaged from the rods they are clipped over.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide an improved bolding strut of the abovedcscribed geneeral type.

Another object is the provision of such a holder strut for the reinforcement of concrete walls which holds the main reinforcement rods of these walls extremely securely.

SUMMARY OF THE INVENTION These objects are attained according to the present invention in a holding strut adapted to secure together a pair of spaced-apart and generally parallel reinforcement rods. This strut according to the present invention has at each end a hook with a radius of curvature that is larger than the diameter of the reinforcing rods to be clipped together. Each of these hooks is provided with a synthetic-resin holder and spacer body which is formed with a seat adapted to receive one of the main reinforcement rods and offset from the center of curva ture of the respective hook. In addition each of these synthetic-resin bodies is formed with a deflectibel tongue lying at an acute angle to the strut at the location on the strut where it is attached and each having one end engageable with the rod so as to hold this rod firmly in place in the seat, while the deflectability of the tongue allows the rod to be slipped between them and fitted into the seat.

The strut according to the present invention'holds the reinforcing rods extremely securely, making it almost impossible for them to slip out of place. In addition the relatively large radius-of curvature'greatly reduces the static notch effect on the synthetic-resin material of the hook. This is particularly the-casewhen, according to the present invention, the hook haszan inner radius of curvature which is at least equal to 1.25 times the diameter of the rod forming the strutand the hooks. 1

Each of the bodies is formed according to the presentinvention on the side of the hook away from the hook end with an inwardly projecting lug which defines with the hook end a gap into which the reinforcement rod is introduced as it is pressed into the seat. One of the deflectable tongues is formed on this lug and the other is'formed on the body at the free end of the hook. thus the reinforcement rod is pushed between these two tongues, spreading them apart, and only allowing them to snap back into place when the rod is snugly in the seat. The seat according to the present invention is a semi-cylindrical surface having the same radius of'curvature as the rod which is to be received in it. In this manner the rod is snugly and virturally immovably held.

BRIEF DESCRIPTION OF THE DRAWING The above and other objects. features, and advantages will become more readily apparent from the following, reference being made to the accompanying drawing in which:

FIG. 1 is a top view partly in section showing an assembly according to the present invention, and

FIG. 2 is a section taken along line IIII of FIG. 1.

SPECIFIC DESCRIPTION As: shown in FIGS. 1 and 2 a space 1 to be filled with concrete so as to form a wall is defined between two like planar forms 2. A pair of like arrays or grids 5 each formed of a plurality of parallel horizontal reinforcement rods 3 and a plurality of parallel vertical rods 4 is situated spaced from each of the forms 2, the vertical rod 4 being outside the horizontal rod 3.

These two grids 5 are joined together by struts as shown at 6, each being formed of an iron or steel rod 7 of circular cross section formed at each end with a hook 8. Each of these hooks 8 terminates in an end region 13 extending at an angle of approximately 165 to the longitudinal axis of the straight central section 7' of the strut 6. Each hook 8 is provided with a syntheticresin holder body 9 completely encapsulating it and itself formed with a rib 10 adapted to engage the inner surface of the respective form 2.

Each of the hook-shaped bodies 9 is formed at its bight with a respective semicylindrical seat 11 adapted to receive a respective rod 4 snugly. this seat 11 having the same radius of curvature as therod 4. The inner surface 12 of the body 9 at hook 8 has a center of curvature K lying wholly outside the rod 4 received in the seat 11. This inner surface 12 has a diameter of curvature D which is equal to at least 2.5 times the diameter (1 of the rod 7. The body 9 is formed with an inwardly directed lug 14 extending toward the free end 13 of the hook 8. The outer end 15 of this lug 14 defines with the end 13 a gap l6 capable of receiving the rod 4. A deflectable tongue 17 has one end formed on one shank of the body 9 adjacent the outer end 13 and another 19 engageable with the rod 4 received in the seat 11. Another deflectable tongue 18 has one end formed on the other shank. atthe lug l4 and another end 19" also engageable with the outer surface 20 of the rod 4. Both of these tongues 17 and 18 extend at acute angles to each other and to the rod 7 at the location where they are attached-to the body 9.

m use. one of the ends of the strut 6 is clipped over one Vertical outer bar4 by introduction of this bar into the gap 16 so that it forces the tongues 17 and 18 apart until it comes to lie in the seat 11 whereupon the tongues 17 and 18 snap into place against the surface 20 ofithe rod 4, thereby securing it tightly in place. Then the other end is similarly clipped on the opposite bar 4. The distance a between the rods 4, and therefore between the two grids 5, is determined by the length of the main section 7' of the rod 7. The distance 12 between the outer edge 21 of the rib 11 and the outer surface of the rod 4 is determined by the shape of the bodies 9. As a general rule four such struts 6 are used for each square meter of the wall. Thus the struts 6 are spaced. apart by a distance equal to approximately 75cm.

Both of the hooks lie to the same side of the main rod section 7'. so that the rod section 7' extends at right angles to the faces of the wall. In addition the large size of the hooks insure that even should the wall or building be damaged by fire so that the synthetic-resin bodies 9 are melted and destroyed the hooks 8 will nonetheless be engaged around the rod 4 and hold the reinforcement array securely together.

lclaim: a

1. A strut for interconnecting a pair of spaced-apart reinforcement rods. said strut comprising:

an elongated bar formed at each end with a hook;

and y g a hook-shaped body of synthetic-resin material molded on each of said hooks each of said bodies conforming to. the respective hook and having a pair of shanks joined at a respective bight, said bodies being formed inside the respective hook at the respective bight with a seat adapted to receive one of said rods and offset from the center of curvature of the respective hook, and with a pair of inwardly extending deflectable tongues each reaching from one of said shanks toward the bight, each of said tongues extending at an acute angle to said bar and said tongues including an acute angle with each other, each of said tongues having an end snugly engageable against a rod in said seat.

2. The strut defined in claim 1 wherein said rods are generally cylindrical and said seat is partcylindrical and snugly engageable with said rods.

3. The strut defined in claim 1 wherein said bar is of circular cross section and said hooks each have an inner radius of curvature greater than the diameter of said rod.

4. The strut defined in claim 3 wherein said radius of curvature is equal to at least 1.25 times said diameter.

5. The strut defined in claim 1 wherein said bar has a generally straight section and a pair of curved sections. said curved sections constituting said hooks, each of said bodies being formed at said location on said straight section with a lug, said one of said fingers extending from said lug, said lug forming with the free end of said curved section a gap.

6. The strut defined in claim 5 wherein the other finger extends from said free end.

7. The strut defined in claim 5 wherein said seat is between the side of said center of curvature corresponding to said straight section. 

1. A strut for interconnecting a pair of spacedapart reinforcement rods, said strut comprising: an elongated bar formed at each end with a hook; and a hook-shaped body of synthetic-resin material molded on each of said hooks each of said bodies conforming to the respective hook and having a pair of shanks joined at a respective bight, said bodies being formed inside the respective hook at the respective bight with a seat adapted to receive one of said rods and offset from the center of curvature of the respective hook, and with a pair of inwardly extending deflectable tongues each reaching from one of said shanks toward the bight, each of said tongues extending at an acute angle to said bar and said tongues including an acute angle with each other, each of said tongues having an end snugly engageable against a rod in said seat.
 2. The strut defined in claim 1 wherein said rods are generally cylindrical and said seat is part-cylindrical and snugly engageable with said rods.
 3. The strut defined in claim 1 wherein said bar is of circular cross section and said hooks each have an inner radius of curvature greater than the diameter of said rod.
 4. The strut defined in claim 3 wherein said radius of curvature is equal to at least 1.25 times said diameter.
 5. The strut defined in claim 1 wherein said bar has a generally straight section and a pair of curved sections, said curved sections constituting said hooks, each of said bodies being formed at said location on said straight section with a lug, said one of said fingers extending from said lug, said lug forming with the free end of said curved section a gap.
 6. The strut defined in claim 5 wherein the other finger extends from said free end.
 7. The strut defined in claim 5 wherein said seat is between the side of said center of curvature corresponding to said straight section. 